I meant, you can make a nova tower, they dont track any target, they just shoot =)
It depends on the boss AI, they are all different, but the game wasn't designed for any in depth modding of behaviours from the beginning, that's why you can't mod classes and can't mod AI outside of the given limits, the limits are pretty much what you find inside the current xmls.
The composite AI is probably the best AI to use, cause you can make most out of it, especially since you can trigger events and have events trigger skills with it.